CRT assembly of projection television

ABSTRACT

A cathode-ray tube (CRT) assembly of a projection television is provided. The CRT assembly includes a CRT for creating an image, a lens for magnifying the image created in the CRT and projecting the image onto a screen, a coupler, disposed between the CRT and the lens, within which a cooling liquid receptacle filled with a cooling liquid is provided, a cooling liquid pouring inlet disposed on one side of the coupler and pouring the cooling liquid into the cooling liquid receptacle, and an oilpack connected to the cooling liquid receptacle so that a portion of the cooling liquid is contained when the cooling liquid filled in the cooling liquid receptacle expands.

CLAIM OF PRIORITY

[0001] This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from my application CRT ASSEMBLY OF PROJECTION TELEVISION field with the Korean Industrial Property Office on Aug. 12, 2000 and there duly assigned Serial No. 00-46766.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention relates to a cathode-ray tube (CRT) assembly of a projection television system, and more particularly, to a CRT assembly of a projection television having a pressure regulating structure for controlling the pressure of a cooling liquid for dispersing heat generated by the CRT.

[0004] 2. Description of the Related Art

[0005] A projection television has been used for displaying an enlarged image on a screen. The enlarged imaged is projected from a cathode-ray tube (CRT) assembly including a CRT, a projection lens, and a coupler disposed between the CRT and the projection lens to couple the projection lense to the CRT. In order to disperse heat generated from the CRT, a cooling liquid receptacle and a pressure receptacle chamber are provided in the coupler.

[0006] As an effort of providing a pressure receptacle chamber, U.S. Pat. No. 4,777,532 to Hasegawa entitled Receiver Projection Apparatus for A Projection Television shows a conventional projection television having a pressure regulating chamber. The greater detailed structure of the conventional projection television is described in the detailed of the Invention.

[0007] The conventional CRT, however, involves drawbacks that the structure of the coupler and the pressure regulating chamber is complicated due to structural elements fixed to coupler and that the manufacturing cost is high due to the large member of parts and the large member of assembling steps.

SUMMARY OF THE INVENTION

[0008] To solve the above problems, it is an objective of the present invention to provide a cathode-ray tube (CRT) assembly of a projection television having an improved structure for controlling the pressure of a CRT cooling liquid contained within a cooling liquid receptacle of a coupler.

[0009] It is another object to provide a CRT assembly having a pressure regulating pack able to be placed in a narrow space within a projection television.

[0010] It is yet another object to provide a CRT assembly having a flexible pressure regulating pack to be easily assembled into the CRT assembly.

[0011] It is still yet another object to provide a CRT assembly having a pressure regulating pack able to reduce the member of parts and the manufacturing cost.

[0012] To achieve the above objective, the present invention provides a CRT assembly of a projection television including a CRT for creating an image, a screen, a coupler, disposed between the CRT and the lens, a cooling liquid receptacle formed in the coupler and filled with a cooling liquid, a cooling liquid pouring inlet disposed on one side of the couple to provide a passageway for the cooling liquid poured into the cooling liquid receptacle, and an oilpack connected to the cooling liquid receptacle so that a portion of the cooling liquid is contained in the oilpack when the cooling liquid filled in the cooling liquid receptacle expands by hear generated from the CRT.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more complete appreciation of this invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:

[0014]FIG. 1 is a schematic cross-sectional view of a general projection television;

[0015]FIG. 2 is a cross-sectional view of a conventional cathode-ray tube (CRT) assembly of a projection television;

[0016]FIG. 3 is a perspective view of a CRT assembly of a projection television according to the principle of the present invention;

[0017]FIG. 4 is a schematic cross-sectional view of the CRT assembly of a projection television shown in FIG. 3;

[0018]FIG. 5 is a partially exploded perspective view of a main portion of the CRT assembly of a projection television shown in FIGS. 3 and 4, and

[0019]FIG. 6 is a cross-sectional view showing a CRT assembly of a projection television according to another embodiment of the invention, in which a pack holder is coupled to a coupler.

DETAILED DESCRIPTION OF THE INVENTION

[0020]FIG. 1 shows a projection television. An image produced and enlarged by a small letter Cathode-ray tube (CRT) assembly 4 installed within a main body 1 is reflected by a reflecting mirror 2 and projected onto a screen 3 disposed in front of main body 1.

[0021] As shown in FIG. 2, conventional CRT assembly 4 includes a CRT 10 for creating an image, a lens 20 for magnifying the image of CRT 10 to project it onto the screen 3, and a coupler 30 for coupling CRT 10 to lens 20. A cooling liquid receptacle 31 filled with a cooling liquid C by coupling CRT 10 to lens 20 is provided inside a frame of coupler 30. On a side of coupler 30 a cooling liquid pouring inlet 32 is disposed on a side of coupler 30 for pouring cooling liquid C into cooling liquid receptacle 31. A rubber buffer 40 and a holder cap 42 are connected to cooling liquid pouring inlet 32 so that cooling liquid C filled in cooling liquid receptacle 31 does not leak out when the volume of cooling liquid C is expanded by heat generated from CRT 10.

[0022] A flange portion 33 having a concave shape is provided for housing rubber buffer 40 connected to cooling liquid pouring inlet 32. With a rubber buffer 40 housed in flange portion 33, holder cap 42 presses a rim of rubber buffer 40 so that rim may be sealed and fastened to coupler 30 by a screw 44. Rubber buffer 40 as a diaphragm prevents cooling liquid C from flowing out of flange portion 33, and when the cooling liquid C expands, it serves to control the pressure of cooling liquid C contained in cooling liquid receptacle 31 while being elastically deformed away from flange portion 33.

[0023] As described above, the conventional projection television CRT assembly includes flange portion 33 housing rubber buffer 40 in coupler 30 and holder cap 42 fixed by screw 44 in order to couple rubber buffer 40 to coupler 30. Thus, the manufacturing of coupler 30 is complicated, and a separate cap holder 42 and screw 44 are required for coupling rubber buffer 40 to coupler 30.

[0024] Referring to FIGS. 3 and 4, a cathode-ray tube (CRT) assembly of a projection television according to the present invention includes a CRT 50 producing an image, a lens 60 magnifying the image of CRT 50 to project the image onto screen 3 of FIG. 1, a coupler 70 coupling CRT 50 to lens 60, and an oilpack 80 coupled to coupler 70. CRT 50 and lens 60 are sealed by coupler 70 when sealing members 51 and 61 are fixed between coupler 70 and CRT 50 or lens 60 through fixed brackets 52 and 62 by screws, respectively.

[0025] Coupler 70 has two opened sides each facing one of lens 60 and CRT 50. This space between the two opened sides and within coupler 70 is a cooling liquid receptacle 71 which will later be filled with a cooling liquid C. A cooling liquid pouring inlet 72 is formed on an inlet member 76 of coupler 70 disposed on a third side of coupler 70 to provide a passageway for pouring cooling liquid C into cooling liquid receptacle 71. Oilpack 80 is a bag-type pack made of two sheets of flexible material, such as vinyl, the edges of which are fused together to form a closed portion 83 and an open end 82. An extended portion 98 of a pack holder 90 is welded to open end 82, and then a supporting portion 95 of pack holder 90 is attached to cooling liquid pouring inlet 72 of coupler 70. During operation of the projection television, the temperature of cooling liquid C filled in cooling liquid receptacle 71 increases to about 90° C. due to heat generated by CRT 50. As the temperature of cooling liquid C increases, the volume of cooling liquid C increases, and then the pressure of cooling liquid receptacle 71 increases. The oilpack 80 receives an excessive portion of cooling liquid C through cooling liquid pouring inlet 72 in order to reduce the pressure, thereby preventing the pressure of cooling liquid receptacle 71 from increasing.

[0026] A through hole 91 is formed in a holding member 93, a supporting portion 95, and an extended portion 98 of pack holder 90 so that cooling liquid C may flow from cooling liquid receptacle 71 into the inside of closed end 83 of oilpack 80. A portion welded to the oilpack 80 is preferably diamond-shaped for easy welding. In this embodiment, an oilpack coupling unit is provided for simply fixing oilpack 80 to coupler 70 in one fixing step.

[0027] Referring to FIGS. 3 and 5, the oilpack coupling unit includes two protrusions 73 formed on cooling liquid pouring inlet 72 and depressions 74 formed on a side of coupler 70, a pair of guiding slots 92 including an axial slot 96 and a round slot 97, a holding portion 93, and a stopper formed on supporting portion of pack holder 90. The protrusions 73 are projected toward a center of cooling liquid pouring inlet 72. One or more depressions 74 are formed on inlet member 76 of coupler 70 adjacent to cooling liquid pouring inlet 72, and preferably two depressions 74 are formed symmetrically around cooling liquid pouring inlet 72 and receive corresponding stopper 94. Two guiding slots 92 are disposed on opposite sides of pack holder 90 so that protrusions 73 are fitted into axial slot 96 and round slot 97 when pack holder 90 is inserted into cooling liquid pouring inlet 72. Holding portion 93 projects out from guiding slot 92 so that pack holder 90 can be caught on the protrusion 73 preventing separation from coupler 70 after axial slot 96 and round slot 97 of guiding slot 92 receives protrusion 73 of cooling liquid pouring inlet 72.

[0028] When pack holder 90 is coupled to coupler 70, an o-ring 85 is provided between supporting portion 95 of pack holder 90 and inlet member 76 of coupler 70 in order to prevent cooling liquid 8 C from leaking out through a crevice between pack holder 90 and cooling liquid pouring inlet 72. Preferably, o-ring 85 is made of rubber material so that o-ring 85 may be elastically deformed when pack holder 90 is coupled to coupler 70. In the course of coupling pack holder 90 to coupler 70, o-ring 85 is elastically deformed and compressed between pack holder 90 and coupler 70. When the coupling is complete, a repulsive force occurs due to elastic recovery tendency of rubber material, so that pack holder 90 is pushed away from coupler 70. In this case, o-ring 85 maintains a sealed state between pack holder 90 and coupler 70 while holding portion 93 is sealed with inlet member 76 and cooling liquid pouring inlet 72.

[0029]FIG. 6 is a cross-sectional view showing a pack holder coupled to a coupler according to another embodiment of the invention. A pack holder 190 is formed so that a path of a through hole 191 communicating both cooling liquid receptacle 71 of coupler 70 and the inside of a closed portion 183 of an oilpack 180 is bent at a right angle within pack holder 190. Also, a hexagonal groove 195 is formed opposite to holding portion 93 of pack holder 190 coupled to inlet member 76 of coupler 70. An open end 182 of oil pack is attached to a bent portion 199 of pack holder 190.

[0030] If oilpack 180 is repeatedly expanded or contracted, the oilpack 180 can be damaged by contact with coupler 70. For this reason, pack holder 190 is right-angled in order to prevent oilpack 180 from contacting coupler 70. Furthermore, when pack holder 190 is connected to coupler 70, friction occurs due to the O-ring 85 sitting between holder back 190 and coupler 70. Thus, the hexagonal groove 195 is formed so that a hexagonal wrench not shown may be used to rotate pack holder 190 and couple to coupler 70.

[0031] In the projection television CRT assembly according to the invention having a structure as described above, a bag-type oilpack 80, 180 is coupled to coupler 70 through pack holder 90, 190 in order to control the pressure of cooling liquid receptacle 71 formed within coupler 70. Thus, when cooling liquid C held in the cooling liquid receptacle 71 expands as the temperature increases 112 with heat generated in CRT 50, cooling liquid C flows into oilpack 80, 180 through a through hole 91, 191 formed on pack holder 90, 190, thereby reducing the pressure of cooling liquid receptacle 71.

[0032] As described in the foregoing, a projection television CRT assembly according to the invention includes a bag type oilpack for receiving cooling liquid contained in a cooling liquid receptacle of a coupler as the temperature of the cooling liquid rises and the cooling liquid expands. This makes it possible to prevent the pressure inside the cooling liquid receptacle from increasing, thereby providing a reliable product. Furthermore, the CRT assembly is constructed such that the oilpack is coupled and fixed to the cooling liquid pouring inlet of the coupler in one step using a holder back, which simplifies assembling and reduces the member of required parts. Accordingly, this reduction in the number of parts and assembling steps reduces the manufacturing cost. 

What is claimed is:
 1. A cathode-ray tube (CRT) assembly of a projection television, comprising: a CRT for creating an image; a lens for magnifying said image created from said CRT and projecting said image onto a screen; a coupler disposed between said CRT and said lens, coupling said lens to said CRT, defining a cooling liquid receptacle filled with a cooling liquid; a cooling liquid pouring inlet formed one side of said coupler, providing a passage way for pouring the cooling liquid into said cooling liquid receptacle; and an oilpack connected to said cooling liquid pouring inlet, communicating said cooling liquid receptacle so that a portion of the cooling liquid is contained in said oil pack when the cooling liquid filled in said cooling liquid receptacle expands and said portion of the cooling liquid overflows from said cooling liquid receptacle.
 2. The CRT assembly of claim 1, wherein said oilpack is made of a material having flexibility so that the volume of a sealed inner space of said oilpack varies by the flow of the cooling liquid into or out of said oilpack depending on the expansion and contraction of the cooling liquid.
 3. The CRT assembly of claim 1, said oilpack further comprising: a pack holder coupled to said cooling liquid pouring inlet, having a through hole communicating both a sealed space of said oilpack and said cooling liquid receptacle of said coupler; and an oilpack coupling means formed on said pack holder, coupling said pack holder to said cooling liquid pouring inlet of said coupler.
 4. The CRT assembly of claim 3, said oilpack coupling means including: a protrusion formed in said cooling liquid pouring inlet of said coupler; a guiding portion formed on said pack holder so that said protrusion is coupled to said guiding portion; and a holding portion formed on said pack holder and disposed within said cooling liquid receptacle to tightly couple said pack holder to said coupler when said protrusion is captured within said guiding portion.
 5. The CRT assembly of claim 4, said oilpack coupling means comprising: a depression formed adjacent to said cooling liquid pouring inlet; and a protrusion formed on said pack holder, inserted into said depression when said pack holder is tightly coupled to said coupler.
 6. The CRT assembly of claim 5, said oilpack coupling means comprising an o-ring disposed between said pack holder and said cooling liquid pouring inlet, preventing the leakage of the cooling liquid.
 7. The CRT assembly of claim 3, said pack holder comprising a supporting portion being L-shaped so that said cooling liquid pouring inlet and one end portion of said pack holder form an angle while the other end portion of said pack holder is coupled and parallel to said cooling liquid pouring inlet.
 8. A cathode ray tube (CRT) assembly of a projection television, comprising; a CRT creating an image; a lens magnifying the image produced from said CRT and projecting the image onto a screen; a coupler disposed between said CRT and said lens, coupling said lens to said CRT, defining a receptacle filled with a cooling liquid; an inlet formed on one side of said coupler, communicating said receptacle; and a pack unit coupled to said inlet, having a pack, a pack holder having a first end coupled to an open portion of said pack and a second end coupled to said inlet, a through hole formed inside of said pack holder and communicated with both said pack and said receptacle.
 9. The CRT assembly of claim 8, said pack unit is detachably attached to said inlet of said coupler.
 10. The CRT assembly of claim 8, wherein said pack is made of a flexible material and includes said open portion and a closed portion accommodating a portion of said cooling liquid flowed from said receptacle through said through hole.
 11. The CRT assembly of claim 10, wherein the volume of said pack varies by the portion of said cooling liquid flowed from said receptacle.
 12. The CRT assembly of claim 8, wherein said first portion and said second portion of said pack holder are perpendicular to each other.
 13. The CRT assembly of claim 8, said first portion of said pack holder including a structure for rotating aid pack holder when said pack holder is connected to said inlet.
 14. The CRT assembly of claim 8, said second portion of said pack holder comprising a supporting portion and a holding portion both disposed on each opposite side of said inlet after said holding portion has been inserted into said inlet.
 15. The CRT assembly of claim 14, further comprising: a protrusion forward on said inlet; and said protrusion inserted into said guiding slot when said second portion is inserted into said inlet.
 16. The CRT assembly of claim 15, further comprising: an axial slot of said guiding slot, said protrusion inserted into said axial slot when said second portion is axially inserted into said inlet; and a round slot of said guiding slot, said protrusion inserted into said round slot when said second portion rotates about a center of said inlet after said second portion has been axially inserted into said inlet.
 17. The CRT assembly of claim 16, further comprising: a depression formed around said inlet; and a stopper formed on said second portion of said pack holder, inserted into said depression after said protrusion has been inserted into said round slot.
 18. The CRT assembly of claim 14, further comprising a ring inserted between said supporting portion and said a side of said inlet to seal said inlet.
 19. The CRT assembly of claim 14, said through hole comprising a first hole portion formed inside of said first portion o said pack holder and a second hole portion formed inside of said second portion of said pack holder, said first hole portion being perpendicular to said second hole portion.
 20. A cathode ray tube (CRT) assembly, comprising: a CRT; a lens projecting an image produced from said CRT onto a screen; a coupler disposed between said CRT and said lense to couple said lens to said CRT, having a receptacle filled with a cooling liquid; a pack having a sealed portion and an open end; a pack holder having one end detachably attached to an inlet of said coupler, having the other end coupled to said open end of said pack; a through hole formed on said one end and said other end of said pack holder, communicating both said receptacle and an inside of said sealed portion of said pack. 